Typical optical fibers include a core material and a cladding material, with each of the core and the cladding being fabricated from fused silica and having dissimilar refractive indices. A fiber can be formed by drawing a preform, which can be a large mass that includes the core and cladding materials arranged in a shape that can resemble across-section of the finished fiber. The preform can be drawn in a fiber drawing tower, such that the preform can be heated and stretched from one end to form the optical fiber. The finished fiber can have a length that can be constrained by a variety of factors, including physical and operational factors such as resulting from Raman gain and/or pump power.
The core material of a typical optical fiber can exhibit optical gain through a phenomenon called stimulated Raman scattering (SRS). Therefore, optical signals can be amplified as they propagate through an optical fiber. Amplification of optical signals via SRS is dependent on both a Raman gain coefficient of the core material and a length of the optical fiber. To achieve desired Raman gain coefficients, optical fiber cores are typically doped with additional materials to increase the optical gain of the fiber. However, such doping has limitations in contributing to a Raman gain coefficient. As a result, to achieve substantial amounts of optical amplification of a given optical signal, some optical fibers have to be fabricated at a length of hundreds of meters or more. Accordingly, some optical systems require a substantial amount of physical space and/or power to maximize optical signal intensity that is provided from an optical pump or laser.